The correct answer is: A. Rate at which RBI borrows money from Commercial Banks.
Reverse repo is a tool used by the Reserve Bank of India (RBI) to control the money supply in the economy. It is the rate at which the RBI borrows money from commercial banks. When the RBI wants to increase the money supply, it lowers the reverse repo rate. This makes it cheaper for banks to borrow money from the RBI, and they are more likely to lend money to businesses and consumers. When the RBI wants to decrease the money supply, it raises the reverse repo rate. This makes it more expensive for banks to borrow money from the RBI, and they are less likely to lend money to businesses and consumers.
The other options are incorrect. Option B is the rate offered to blue chip companies. Option C is the bank rate. The bank rate is the rate at which the RBI lends money to commercial banks. Option D is none of the above.